Vol15 No.10: 2266-2275
【Title】Source tectonic dynamics features of Jiuzhaigou Ms 7.0 earthquake in Sichuan Province, China
【Author】YI Shu-jian1,2,3; WU Chun-hao2,3; LI Yu-sheng1*; HUANG Chao1
【Addresses】1 State Key Laboratory of Geohazard Prevention and Geoenvironment Protection, Chengdu University of Technology, Chengdu 610059, China; 2 Key Laboratory of Mountain Hazards and Surface Process, Institute of Mountain Hazards and Environment, Chinese Academy of Sciences, Chengdu 610041, China; 3 University of Chinese Academy of Science, Beijing 100049, China
【Corresponding author】LI Yu-sheng
【Citation】Yi SJ, Wu CH, Li YS, et al. (2018) Source tectonic dynamics features of Jiuzhaigou Ms 7.0 earthquake in Sichuan Province, China. Journal of Mountain Science 15(10). https://doi.org/10.1007/s11629-017-4703-6
【Abstract】On August 8, 2017, a Ms 7.0 earthquake occurred 5 km to the west of Jiuzhaigou National Park, causing 25 deaths and injuring 525. The objective of this study was to explore the seismogenic fault of the earthquake and tectonic dynamics of the source rupture. Field investigations, radon activity tests, remote sensing interpretations, and geophysical data analyses were carried out immediately after the earthquake. TheJiuzhaigou earthquake occurred at the intersection of the northern margin of the Minshan uplift belt and the south part of the Wenxian–Maqin fault in the south margin of the West Qinling geosyncline. There are two surface rupture zones trending northwest (NW), which are ground coseismic ruptures caused by concealed earthquake faults. The rupture on the southwest is the structure triggering the earthquake, along the Jiuzhaitiantang–Epicenter–Wuhuahai. The other one on the northeast (Shangsizhai–Zhongcha–Bimang) is a reactivation and extension of the secondary fault trending NW. The source rupture of this earthquake is a strike-slip shear fracture associated with the fault plane trending NW 331° and steeply dipping 75°, which is continuously expanding at both ends. The tectonic dynamics process of the source rupture is that the "Jiuzhaigou protrusion" is left-lateral sheared along the seismogenic fault in the NW direction. Finally, the Maqin fault and the arc fault system at the top of the "Wenxian protrusion" will be gradually broken through sometime in far future, as well as earthquake-triggered landslides will be further occurred along the narrow corridor between the seismogenic faults. The research results revealed the basic geological data and tectonic dynamic mechanism in this earthquake.
【Keywords】Jiuzhaigou; Earthquake; Surface rupture; Tectonic dynamics; Radon activity